Yes I totally agree with the additional cooing from environmental effect will apply but as you say
Will limit the max tork needed to pull off. The higher volt battery won’t help with the tork and I’m presuming the stator is saturated as it’s not that large of a motor at 1300W makes me suspect it is. There is ways around this such as gearing. I would guess it take 60A ish to start moving some thing like this with a good punch of tork to push you up a ski slope.